Exposure to Polycyclic Aromatic Hydrocarbons and Male Sperm Quality Polycyclic aromatic hydrocarbons (PAHs) are one of the most ubiquitous environmental pollutants. Humans are constantly exposed to complex mixtures from a variety of sources. Increasing evidence from animal studies has shown that PAHs, byproducts of the fuel combustion process, contribute to dysfunction of male rat sperms. At the same time, the effects of PAHs on human male sperms have been inconclusive based on the limited results from epidemiologic studies. We propose a longitudinal study to assess the effect of PAHs on male spermatozoa of human subjects. The central hypothesis is that PAH exposure contributes to decreased sperm quality of coke-oven workers. Our specific aims are to i) assess sperm quality of coke-oven workers;ii) determine the correlation between sperm chromatin integrity and PAH biomarkers;iii) determine sperm oxidative damage by identifying specific DNA lesions. The longitudinal study includes repeated measurements to account for PAH exposure as it relates to toxic effects on sperms during spermatogenesis. Personal breathing-zone air samples and urine samples will be collected to determine PAH external and internal exposure levels, respectively. Semen will be collected to assess sperm quality, DNA adducts, and oxidative damage. Features of this design include efficient control for confounding factors, accurate exposure ascertainment, and sufficient power to detect exposure related changes in sperm quality. Research results are useful to lay a foundation for future study related to the effects of PAHs on reproductive health. Also, the results can be useful for reforming best management practices and policies, thus protecting the reproductive health of individuals and/or workers exposed to PAHs. Thus, this proposed study is in line with the mission of the National Institute of Environmental Health Sciences and the National Institute for Occupational Safety and Health to reduce the burden of human dysfunction from environmental and occupational causes by understanding how PAHs interrelate with male reproductive health. PUBLIC HEALTH RELEVANCE: The longitudinal study aims to assess alteration of male sperm quality and DNA oxidative effects caused by occupational exposure to PAHs.